Manipulator using plane pulse motor

ABSTRACT

In order to obtain a manipulator using a plane pulse motor showing advantageous features such that even in a case where a moment of force is applied to the manipulator in a falling direction, the moment can be sustained by magnetic attraction caused by the pulse motor, the weight of the manipulator is reduced, the degree of freedom of the movement can be increased, and a rotating mechanism for a tool itself is eliminated; a plurality of movable members are provided on a stator of the plane pulse motor, a rotatable shaft is provided on each movable member so as to extend vertically, the rotatable shafts are connected with each other through a connecting member, a required tool is secured to the connecting member, and the movements of the movable members are made controllable in a manner correlated with each other. The manipulator using the plane pulse motor of the aforementioned construction is most adapted to be used in combination with an industrial robot and the like.

TECHNICAL FIELD OF APPLICATION

This invention relates to a manipulator whose degree of freedom isimproved by use of a plane pulse motor freely driven in atwo-dimensional manner.

BACKGROUND OF THE INVENTION

As shown in FIGS. 11 and 12, a plane pulse motor comprises a stator 10having a number of magnetic pieces 100 that are formed by dividing aplanar surface of a magnetic substance by orthogonal grooves into alattice form having a suitable pitch, and also a movable member(armature) 20 comprising two perpendicularly arranged magnetic polemembers 103. Each of the magnetic pole members 103 comprises a pluralityof magnetic pieces 101, 102 formed out of permanent magnets, each havinga plurality of magnetic pole legs with a pitch deviating from the pitchof the lattice of the stator 10 by a half pitch. By the attracting forceof the magnetic pole members 103, the movable member 20 of the planepulse motor is held on the surface of the stator 10, and by controllingexciting coils 104 wound around the magnetic pieces 101 and 102, themovable member 20 is shifted in an arbitrary direction along the surfaceof the stator 10. For smoothing the movement of the movable member 20along the surface of the stator 10, air is injected between the member20 and the stator 10 as shown by an arrow mark A so as to form an airlayer.

It is apparent that the stator 10 with the movable member 20 attractedthereon, may be placed not only on the floor, but also on either theside walls or ceiling of a structure.

Because of the above described construction, the plane pulse motor hasbeen heretofore used in combination with a manipulator with a requiredtool secured to an output shaft of the manipulator for implanting, forinstance, electronic parts on a printed circuit board.

In the case of actual application, however, besides the aforementionedarbitrary movement of the movable member 20 along the surface of thestator 10, further degrees of freedom, such as movements around andalong the output shaft 105 of the movable member 20, are required.Accordingly, it becomes necessary to mount a separate actuator such as arobot 106 having a rotatable arm as shown in FIG. 10 instead of theoutput shaft 105 of the movable member 20. However, in a case where amoment M of a falling direction is applied to the movable member 20 as aresult of the provision of the separate actuator, the moment M must berestricted in a range not exceeding the moment-withstanding capabilityof the attracting force applied to the movable member 20, andfurthermore, there arise problems such as increasing weight because ofthe actuator, increasing the size of the movable member 20, andcomplicating the control of the same.

The object of the present invention is to provide a manipulator using aplane pulse motor wherein the above described problems of theconventional arrangement are eliminated, the construction is simplifiedand the size is reduced regardless of the provision of a plurality ofmovable members, while the operation thereof is stabilized, and thedegree of freedom of the movement is increased.

DISCLOSURE OF THE INVENTION

In order to achieve the above described object of the present invention,there is provided a manipulator using a plane pulse motor constructedsuch that a plurality of movable members are provided on a stator of theplane pulse motor, a rotatable shaft is provided on each movable memberso as to extend vertically, the rotatable shafts are connected with eachother through a connecting member, a required tool is secured to theconnecting member, and the movements of the movable members are madecontrollable in a manner correlated with each other.

According to another embodiment of the present invention, there isprovided a manipulator using a plane pulse motor constructed such that aplurality of movable members are provided on a stator of the plane pulsemotor, a rotatable shaft is extended vertically from one of the movablemembers, one end of a link is pivotally connected to the rotatableshaft, another rotatable shaft is extended vertically from the other ofthe movable members, one side end of two parallel links extending in aspaced apart relation is pivotally connected to another rotatable shaft,a connecting member is pivotally connected to the other end of the oneand two links such that a parallelogrammic link mechanism is formed bythe connecting member and the two links, a required tool is secured tothe connecting member, and the movements of the movable members are madecontrollable in a manner correlated with each other.

According to still another embodiment of the present invention, there isprovided a manipulator using a plane pulse motor constructed such that aplurality of movable members are provided on a stator of the plane pulsemotor, a rotatable shaft is provided on each movable member so as toextend vertically, the rotatable shafts are connected directly orthrough links to a connecting member, a tool supporting spindle issecured to the connecting member, a cover is provided so as to surroundthe tool supporting spindle and to cover the movable members and theconnecting member, and permanent magnets and air bearings are providedon an annular member of the cover, held in opposition to the stator ofthe plane pulse motor.

According to still another embodiment of the invention, there isprovided a manipulator using a plane pulse motor constructed such that aplurality of movable members are provided on a stator of the plane pulsemotor, a rotatable shaft is provided on each movable member so as toextend vertically, a connecting member having a length longer than thedistance between the movable members is provided to interconnect therotatable shafts, a required tool is secured to each end of the lengthof the connecting member, and the movements of the movable members aremade controllable in a manner correlated with each other.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a profile view, partly sectioned, showing a preferredembodiment of this invention;

FIG. 2 is a top plan view showing the embodiment shown in FIG. 1;

FIG. 3 is a top plan view showing another embodiment of the invention;

FIG. 4 is a profile view, partly sectioned, showing still anotherembodiment of the invention;

FIG. 5 is a top plan view of the embodiment shown in FIG. 4;

FIG. 6 is a profile sectional view showing still another embodiment ofthe invention;

FIG. 7 is a top plan view, partly sectioned, showing the embodiment ofFIG. 6;

FIG. 8 is a profile sectional view showing still another embodiment ofthe invention;

FIG. 9 is a top plan view showing a further embodiment of the invention;

FIG. 10 is a profile view showing a conventional example;

FIG. 11 is a perspective view showing a general construction of a planepulse motor; and

FIG. 12 is an explanatory diagram showing the relation between themagnetic pole member and the stator.

EMBODIMENTS MOST ADAPTED FOR PRACTICING THE INVENTION

Preferred embodiments of the manipulator using the plane pulse motoraccording to the present invention will now be described with referenceto the accompanying drawings.

In an embodiment shown in FIGS. 1 and 2, there is provided a stator 10having magnetic pieces constructed in a lattice form or arrangement ofan X-Y axis, but is simply depicted as a plane. Such illustration isapplied to all of the embodiments, and the plan view of the stator 10 isomitted. Numerals 20A and 20B designate movable members (or armatures)of a plane pulse motor similar to the movable member of the conventionalexample. Bearing housings 21A and 21B are secured onto the movablemembers 20A and 20B, respectively. Bearings 22A and 22B are encased inthe bearing housings 21A and 21B, respectively, for supporting rotatableshafts 23A and 23B that extend perpendicularly to the surface of thestator 10 rotate about a Z-axis. Upper ends of the rotatable shafts 23Aand 23B are secured to the corresponding end portions of a connectingmember 24. A tool supporting arm 26 is fixedly secured to the connectingmember 24 through a vertically extending shaft 25. Lead wires forcontrolling the movable members 20A and 20B and hoses leading to airbearings provided between the movable members 20A and 20B and the stator10 are all omitted for simplifying the drawings.

With the aforementioned construction where the vertically extendingrotatable shafts 23A and 23B are mounted rotatably on the movablemembers 20A and 20B provided on the stator 10 in a spaced apartrelation, and the rotatable shafts 23A and 23B are secured to both endsof a connecting member 24, when the movable members 20A and 20B aremoved in a direction under the control of not illustrated control means,for instance, the tool supporting arm 26 secured to the tool supportingshaft 25 is allowed to move along the axis, y axis, or in an obliquedirection. Otherwise, when only the movable member 20B is moved in thearrow-marked direction F2, the tool supporting arm 26 may be rotated ina direction U around the movable member 20A.

Furthermore, when both of the movable members 20A and 20B are movedaround the tool supporting vertical shaft 25 in the same rotatingdirection, the tool supporting arm 26 on the connecting member 24 may berotated in a direction T, and therefore a rotating mechanism forrotating tool as in the case of the conventional construction can beeliminated.

When the rotating arm 26 is rotated by the rotating mechanism, the axialline of the rotating arm 26 tends to be displaced from the axial line ofthe connecting member 24 (FIG. 2 shows a case of 90° displacement), anda moment M of a falling direction tends to occur as shown in FIG. 10.Although in the above described embodiment, this moment M is shared bytwo movable members, in a case where another movable member 20C isadditionally provided as shown in FIG. 3, the rotating operation of thearm and the like can be carried out far more stably.

In still another embodiment shown in FIGS. 4 and 5, brackets 31A and 31Bare secured to the shafts 23A and 23B rotatably supported by the movablemembers 20A and 20B. The bracket 31A has a length in the axial directionof the connecting member 24, somewhat larger than that of the bracket31B, and through bearings (not shown), the bracket 31A rotatablysupports two pivotal shafts 33A and 33C provided at the lower ends oftwo links 35A and 35C, at positions spaced apart by a suitable distancein a direction perpendicular to the rotatable shaft 23A. On the otherhand, the connecting member 24 is provided with pivotal shafts 34A and34C in the vicinity of one end thereof, and the upper ends of the link35A and 35C are pivotally supported by the pivotal shafts 34A and 34C,respectively, supported by the pivotal shafts 34A and 34C, respectively,so that a parallelogrammic link mechanism is formed by the two links35A, 35C, the bracket 31A, and a part of the connected member 24. In thevicinity of the other end of the connecting member 24 is provided apivotal shaft 34B that pivotally supports one end of another link 35B.The bracket 31B secured to the vertical shaft 23B supports anotherpivotal shaft 33B extending perpendicularly to the rotatable shaft 23Bthrough a bearing 22B, and the other end of the link 35B is secured tothe pivotal shaft 33B.

The embodiment can operate in the same manner as that shown in FIGS. 1and 2, and furthermore, by moving the movable members 20A and 20B towardor away from each other in the axial direction of the connecting member24 (in the direction of the arrow mark B in FIG. 5) it is made possibleto move the connecting member 24 upwardly and downwardly in thedirection of z axis, so that a mechanism for driving the tool secured toa tool securing spindle 25 in z direction can be eliminated.

Since a parallelogrammic link mechanism is formed by the two links 35A,35C, bracket 31A, connecting member 24, and the pivotal shafts 33A, 33C,34A, 34C, the connecting member 24 can be controlled to maintain ahorizontal posture without requiring any outside force, and thereforethe tool supporting spindle 25 can be controlled by merely operating theplane pulse motor.

Still another embodiment shown in FIGS. 6 and 7 is constructed in asimilar manner to the embodiment shown in FIGS. 1 and 2, andfurthermore, a cover 42 is provided to cover the movable members 20A and20B and the connecting member 24 entirely, and to encase the toolsupporting spindle 25 via a bearing 41. An annular member 43 is securedto the outer periphery of the cover 42 in an opposing relation to thestator 10, and at least a number of positions of the annular member 43are provided permanent magnets 44 and air bearings 45 that blow out airto form a slight air gap.

In still another embodiment shown in FIG. 8, a connecting member 24 ismoved through links 36 in the direction of A according to the movementof the movable members 20A and 20B. A cover 42 is also provided suchthat a tool supporting spindle 25 is movable therethrough via aslide-bearing 45, and permanent magnets 44 are provided along theannular member 43 as in the embodiment shown in FIGS. 6 and 7.

Although in the above described embodiments, the stator 10 is providedon a floor surface such that the movable members are movable thereon, itis apparent that the stator 10 may otherwise be provided on a side wallor ceiling.

In still another embodiment shown in FIG. 9, a connecting member 24ahaving a length larger than the distance between the movable members 20Aand 20B is supported by the rotatable shafts 23A and 23B provided on themovable members 20A and 20B such that both ends of the connecting member24a project outwardly from the movable members 20A and 20B, and toolsupporting spindles 25a and 25b are secured to the ends of theconnecting member 24a.

When the tool supporting spindle 25a is to be rotated in the directionof an arrow mark A, the movable member 20A is displaced in the directionof arrow mark E while the movable member 20B is held in its position ordisplaced in the direction of arrow-mark H. In the latter case, themovement of the tool supporting spindle 25a is made faster than that ofthe former case.

Likewise, when the tool supporting spindle 25a is to be rotated in thedirection of arrow-mark B, the movable member 20A is displaced in thedirection F while the movable member 20B is held in its position ordisplaced in the direction of arrow-mark G.

The rotation of the tool supporting spindle 25b in the direction ofarrow-mark C or D may be carried out in a similar manner.

Not only the above described rotation, the tool supporting spindle 25aor 25b may be operated in a linear manner in a desired direction.

Since the connecting member 24a of this embodiment is made longer sothat both ends of the member 24a project outwardly in excess of themovable members 20A and 20B, and since the member 24a is secured to therotatable shafts 23A and 23B, the balance of the connecting member 24ais substantially improved, and even in a case where a heavy tool isattached to the tool supporting spindle provided at one end of theconnecting member 24a, there is no possibility of upsetting or incliningthe movable members 20A and 20B.

Furthermore, the tool supporting spindles 25a and 25b are secured toboth ends of the connecting member 24a, and therefore in a case wheretwo assembling or production lines are provided in parallel spaced apartby a distance, it is made possible to carry out assembling or producingoperations of these lines substantially simultaneously by themanipulator placed between these lines.

INDUSTRIAL APPLICABILITY

Since a manipulator using a plane pulse motor according to the presentinvention is constructed such that a plurality of movable members areprovided on a stator of the plane pulse motor, a rotatable shaft isprovided on each movable member so as to extend vertically, therotatable shafts are connected with each other through a connectingmember, a required tool is secured to the connecting member, and themovements of the movable members are made controllable in a mannercorrelated with each other, it is possible to stabilize the seizure ofthe tool, to improve capability of withstanding the movement, toincrease the degree of freedom by displacing the movable memberssimultaneously or separately, and to omit the provision of a rotatingmechanism for the tool.

Furthermore, the manipulator may otherwise be constructed such that itcomprises: a link having an end pivotally secured to the rotatable shaftof one of the movable members; two parallelogrammic links havingone-side ends pivotally secured to the rotatable shaft of the othermovable member; and the connecting member pivotally secured to the otherside ends of the links, with the tool secured to the connecting member;and therefore are obtained advantages such as increasing the degree offreedom of tool, omitting a mechanism for moving the tool in zdirection, simplifying the control of the entire manipulator, holdingthe connecting member horizontally without any outside force because ofthe provision of the parallelogrammic link mechanism, and enabling tocontrol the tool supporting spindle by use of the plane pulse motor.

In a case where a cover is provided so as to surround the toolsupporting spindle and to cover the movable members and the connectingmember, while an annular member is provided at an end edge of the coverfacing the stator, with permanent magnets and air bearings providedaround the annular member; the mechanical portion inclusive of themovable members can be protected from dust and a corrosive atmosphere,the support of the tool supporting spindle is ensured, and a smoothmovement of the movable members is made possible without being disturbedby the cover.

In a case where tool supporting spindles are provided at both ends of along connecting member supported by two movable members, the manipulatormay be operated on both sides thereof simultaneously.

Accordingly, the manipulator using a plane pulse motor of this inventionmay be utilized most suitably in a field of, for instance, a totallyautomated system in a production facility, where the tool is required tobe controlled at an extremely high precision by a simplest mechanism.

What is claimed is:
 1. A manipulator using a plane pulse motor with astator, comprising:a plurality of movable members provided on the statorof the plane pulse motor, said stator having magnetic pieces constructedin a lattice arrangement on an X-Y plane, each of said movable memberssupporting a bearing housing and a bearing housed in said bearinghousing, the bearing of each of said movable members rotatably supportsa rotatable shaft, and each of said rotatable shafts extends along aZ-axis and is adapted for rotation about the Z-axis; a connecting memberthat includes end portions, each of said end portions being connectedwith a respective one of said rotatable shafts such that movement ofsaid movable members is controllable in a correlated manner; and a toolsupporting arm connected to said connecting member.
 2. A manipulator asrecited in claim 1 further comprising air bearings provided between saidmovable member and said stator.
 3. A manipulator as recited in claim 1further comprising a Z-axis support shaft interconnecting said toolsupporting arm to said connecting member.
 4. A manipulator as recited inclaim 1 wherein said tool supporting arm is fixedly secured in positionwith respect to said connecting arm and wherein said connecting arm andtool supporting arm are each elongated and extend perpendicular to eachother.
 5. A manipulator as recited in claim 1 wherein said connectingmember includes a central area and three outwardly extending arms eachhaving an end region defining one of said end portions that is connectedwith a respective one of said rotatable shafts.
 6. A manipulator asrecited in claim 1 wherein said connected member is directly attached tosaid rotatable shafts at a first and a second attachment point and saidconnecting member extends both between said attachment points andexternal to each of said attachment points.
 7. A manipulator using aplane pulse motor with a stator, comprising:a plurality of movablemembers provided on the stator of the plane pulse motor, said statorhaving magnetic pieces constructed in a lattice arrangement on an X-Yplane, a first and a second rotatable shaft supported, respectively, bya first and a second of said movable members, said rotatable shaftsbeing supported so as to extend in a Z-axis direction and said rotatableshafts being adapted for rotation about a Z-axis, a first link having afirst end connected to the first rotatable shaft; a connecting memberhaving a first end portion pivotably connected to a second end of saidfirst link; a bracket supported by said second rotatable shaft; secondand third links each having a first end pivotally connected to saidbracket, said second and third links each further having a second endpivotally connected to a second end portion of said connecting membersuch that said second and third links form a parallelogrammic linkmechanism which, together with said first link and connecting member,provides for correlated movement of said first and second movablemembers; and a tool supporting device secured to said connecting member.8. A manipulator as recited in claim 7 further comprising air bearingsprovided between said movable member and said stator, and wherein saidtool supporting device includes a spindle fixedly secured to anintermediate portion of said connecting member and extending along aZ-axis.
 9. A manipulator using a plane pulse motor with a stator,comprising:a plurality of movable members provided on the stator of theplane pulse motor, said stator having magnetic pieces constructed in alattice arrangement on an X-Y plane; rotatable shafts; each of saidmovable members supporting a bearing which rotatably supports arespective one of said rotatable shafts such that said rotatable shaftsextend along a Z-axis and rotate about said Z-axis; a connecting memberhaving a first and a second end portion, said first end portion beingconnected to a first of said rotatable shafts and the second end portionbeing connected to a second of said rotatable shafts; a tool supportingdevice secured to said connecting member; a cover which is dimensionedand arranged to surround said tool support spindle and to cover saidmovable members and said connecting member, said cover further includingan annular member; and permanent magnets and an air bearing provided onthe annular member of said cover so as to be held in opposition to thestator.
 10. A manipulator as recited in claim 9 wherein said connectingmember is directly attached to said rotatable shafts.
 11. A manipulatoras recited in claim 9 further comprising links, a first of said linksextending from the first end portion of said connecting member to one ofsaid rotatable shafts and a second of said links extending from thesecond end portion of said connecting member to a second of saidrotatable shafts.
 12. A manipulator as recited in claim 11 wherein saidfirst and second link members share a common pivot axis with respect tosaid connecting member, and said cover includes a slide bearing throughwhich said spindle extends, said link members, cover, and spindle beingdimensioned and arranged such that said spindle is shiftable within saidbearing along a Z-axis upon movement of said movable members.
 13. Amanipulator using a plane pulse motor with a stator, comprising:aplurality of movable members provided on the stator, said stator havingmagnetic pieces constructed in a lattice arrangement on an X-Y plane,each of said movable members supporting a bearing which rotatablysupports a rotatable shaft, each of said rotatable shafts extendingalong a Z-axis and adapted for rotation about the Z-axis; a connectingmember interconnecting said rotatable shafts and having a length along acentral axis of said connecting member which is larger than a distanceextending along the central axis of said connecting member between saidrotatable shafts, said connecting member interconnecting said movablemembers so as to provide for correlated movement between said movablemembers; a first tool support member connected to a first end of saidconnecting member; a second tool support member connected to a secondend of said connecting member;
 14. A manipulator as recited in claim 3wherein said tool support members are spindles each supporting arequired tool and said manipulator further comprising air bearingspositioned between said movable members and said stator.